Comparative Analysis of Eccentric Glenosphere in Reverse Total Shoulder Arthroplasty: A Computer Simulation Study

• Published in: International journal of general medicine 2023-10, Vol.16, p.4691-4704
• Main Authors: Xu, Xiaopei, Sun, Qingnan, Liu, Yang, Wang, Dong, Diao, Shuo, Wang, Hanzhou, Gao, Yuling, Lu, Tianchao, Zhou, Junlin
• Format: Article
• Language: English
• Subjects: Arthroplasty; Comparative analysis; Computer simulation; Computer-generated environments; glenosphere eccentricities; impingement; muscle length; notching; Original Research; range of motion; reverse shoulder arthroplasty; Simulation methods
• ISSN: 1178-7074; 1178-7074
• DOI: 10.2147/IJGM.S426191

Objective: The aim was to evaluate the effects of different glenosphere eccentricities on impingement, range of motion (ROM), and muscle length during standard activities in reverse total shoulder arthroplasty (RSA). Methods: In this study, we utilized computational modeling techniques to create native shoulder and shoulder models undergoing RSA and simulate shoulder movements in all abduction-adduction, flexion-extension, and rotation. We tested a total of 36 different glenosphere configurations, which included three different inferior tilts (0[degrees], +10[degrees], +20[degrees]) and two different lateral offsets (0 mm and +4 mm), as well as six different glenosphere eccentricities (concentricity, inferior, posterior, anterior, anteroinferior, and poster-oinferior). We evaluated the maximum impingement-free ROM, impingement sites, and muscle lengths. Results: All glenosphere configurations exceeded 50% of native shoulder ROM in three planes and total global ROM. In abduction-adduction, there was no significant difference among the different glenosphere eccentricities (p > 0.05). In flexion-extension, the posteroinferior eccentricity had the maximum ROM among the different eccentricities, but no significant difference among the different glenosphere eccentricities (p > 0.05). In rotation, there was a significant difference overall, and anteroinferior eccentricity had a significant advantage over concentricity (p < 0.05). In total global ROM, anteroinferior eccentricity had a significant advantage over concentricity when lateral offset was 0 mm (p < 0.05). In all models of glenosphere eccentricities, only the elongation of the infraspinatus muscle was statistically significant (p < 0.05). Conclusion: Glenosphere eccentricity significantly influenced rotation, total global ROM, and the length of the subscapularis muscle. Among them, anteroinferior offset achieved the maximum ROM in abduction-adduction, rotation, and total global activities. Both anteroinferior and inferior glenoid eccentricity showed significant advantages over the concentricity in rotation and total global ROM. Level of Evidence: Basic Science Study; Computer Modeling. Keywords: reverse shoulder arthroplasty, glenosphere eccentricities, impingement, notching, range of motion, muscle length